Gear transmission



Aug. 19, 1930. K. BRAREN 1,773,563

GEAR TRANSMISSION Filed May 24, 1928 2 Shuts-Sheet. 1

Aug. 19, 1930. 1.. K. BRAREN GEAR TRANSMISSION Filed May 24, 192a Z Shuts-Sheet. 2

QS M wn W .9 M //M I on g X I Q I l R m @k mm nu R P atentedu 19,, 1930 UNITED srAras PATENT orrlca LORENZ KON'BAD BEADED, OI. IUN ICH, GERMANY, ASSIGNC JR TO THE FIRM FRIED- nron maox'mi, rnlizrsrousxaomm omm UIl'D MABCHINENBAU, OF MUNICH, BAVABIA,

sass. rnansnnssxon Application filed Kay 24, 1928, Serial 110. 286,284, and in Germany June 18, 1927.

The invention relates to gear transmissions and has for its object to provide a transmission with a fixed speed ratio of a very simple, compact and durable form. This ohject is attained by arranging an intermediate disc in engagement with the fast and slowly rotating members. This disc is mounted eccentrically on the fast member and carries a set of members engaging with teeth of two discs of which one is fastened to or forming 7 part of the slow shaft while the other one is held stationary. The teethon both these discs form equidistants to continuous cycloidal curves. 'Of the curves onthese two discs one is an e icycloid or epitrochoid while the other is an liypocycloid or hypotrochoid. I preferably use a prolate epi-' and hypotrochoid. I

Another object of my invention is to secure axially both the fast and the slowly rotating shafts independently of each other 'and to provide suflicient axial play for the enga 'ng means.

I urthermore according to my invention construct the transmission with roller bearings of special construction.

Another important .object of my invention is to rovide guiding means for the coolin air oi an electric motor where the usua course of circulation is obstructed by a trans mission gear builtinto the end shield of the motor.

The above and various other improvements will be hereinafter fully described and claimed. In order that this my invention maybe more readily understood reference is made to the accompanyin sheets of drawings which show how the invention may be carried into practical effect. I Fig. 1 is a longitudinal section of a car transmission built into the end shield 0 an electromotor.

- Fig'2 is a cross section of the. transmission races and guideways forthe rollers.

Referring to the Figures 1 and 2 the fast rotating shaft 1 in the present instance the armature shaft of an electric motor fits with a flat key like portion 2 into a slot of the crank shaft 3. A circular turned down part 4 on shaft 1 extends beyond the key like portion 2 and fits into a bore of the shaft 3.

The shaft 3 is journaled in two roller bear ings 5'and 6 the shaft itself forming the The outer race 7 of the bearing 5 is. held by two hardened plates 8 and 9 to the cover 10 of the transmission housing 11 which latter at the same time serves as end shield for. the electromotor 12. The rollers of the bearing 6 run in the bore of a part 13, pressed onto a shaft 14 both parts 13 and 14 together forming the slowly rotating member. The division is only made for convenience of manufacture. his member is journaled in roller 'bearlngs 15 and 16. Here again the rollers are running in grooves provided on the shafts 13, 14. The outer race 17 for the bearing 15 is located between two side plates 18 and 19 in a recess of the body 11 and held there by a number of conical set screws 20 pressing the complete bearing against a shoulder of the housing 11 while the race 21 for the bearing 16,is pressed into a recess of the body 11. Thus the fast and slowly rotating shafts are held axiall independently of each other.

An interme iate disc 22 is mounted with its separate hardened hub 23 on two roller bearings 24 and 25 eccentric on the shaft 3. A groove in the shaftguides sideways the rollers ofthe bearing 24. A plate riveted to the hub 23 together with a shoulder in the bore of this hub hold axially the intermediate disc. Onthe intermediate disc 22 there are mounted evenly spaced a number'of engaging members each consisting of a pin 26 pressed into the body of the intermediate disc with a recess for receiving a number of rollers 27 and a bush ing. 28. Thebore of this bushing forms the outer race for the roller bearing. Thebushing 28 is not restrained axially by the rollers 27 but is held in place by a face 29 of the transmission housin 11. A counterweight 30 keyed to the sha I 3 balances the intermediate disc 22 moving ecoentrically, In

order to prevent lubricant being forced in excess into and through the bearing 5 by the counterweight a circular plate 31 hasbeen fastened to the counterweight.

The members on the intermediate disc 22 engage on the inside with teeth 32 formed on a portion of the slowly rotating member 13 and on the outside with teeth 33 on a disc 34 clamped between the cover 10 and the transmission body 11. Both sets of teeth form a continuous cycloidal curve one, preferably the external curve on the member 13, an epicycloid or epitrochoid with the number of teeth 32 one smaller than the number of engaging members on the intermediate disc and the other, the internal curve on the disc 34, an hypocycloid or hypotrochoid with the number of teeth 33 one larger than the number of engaging members. With the curves as indicated and the outer member stationary the sense of rotation of the two shafts 3 and 13, 14 in relation to each other is opposite and the ratio of reduction is one half the number of teeth 32 to one. But with the shaft 13, 14 held stationary and the housing 11 free to rotate the sense of rotation of the shaft 3 and the housing 11 will be identical and the ratio of reduction one half the number of teeth 33 to one. In order to obtain a smooth shape the prolate type of curve with the generating point located inside of the rolling circle is preferably chosen. The curves actually used of course must be equidistants which are determined by the radius of the engaging members.

The circulation of air for cooling an electro-motor becomes quite difiicult when restricting the free axial inflow as is the case with the gear transmission built directly into the end shield. The usual flow of air is indicated on Figure 3. In order to overcome these difliculties a guide 35 for instance a thin shield of conical shape is held by the screws 36 fastening the cover 10 to the transmission body 11. This guide extends close to the ventilating fan 37 of the motor 12 and prevents the forming of an air current resembling in shape a circular ring as indicated by the dotted lines on Figure 1, which is more or less the case with axial restriction. The fan may be located further back entirely within the windings without impairing the efiiciency of the circulation of air. Such a shield of course may also be used to advantage with an ordinary electric motor, having a large hearing or carrying a closed pulley right up against the end shield.

A modified arrangement of the curves is shown on the Figures 4 and 5. On the fast shaft 51 there is mounted to rotate eccentrically an intermediate disc 52 carrying a set of evenly spaced rollers 53 and 54 two on each pin engaging with two curves 55 and 56 of which the latter is fastened to the transmission housing 57 while the former is part of the slowly rotating shaft 58. One of the curves is a continuous epicycloid or -trochoid with a number of teeth one less than the number of engaging members, while the other is a-continuous hypocycloid or -trochoid with a number of teeth or more than the number of engaging members. The ratio of speed is one half the number of teeth on the movable curve. Similarly the two curves may be arranged both outside of the engaging members.

Having now particularly described and ascertained the nature of this my invention and in what manner the same is to be performed, I do not wish to be understood as limiting myself to the'exact details of construction as obviously many modifications will occur to a person skilled in the art.

What I claim is:

1. In a gear transmission a fast rotating member, a slowly rotating member, an intermediate disc mounted to turn eccentrically on said fast member, a set of rollers mounted evenly spaced on said intermediate disc and two members with tooth like projections both in engagement with said engaging rollers, one of said toothed members fastened to said slowly rotating member and the other of said toothed members held against rotary movement, the teeth on one of said toothed members forming part of a continuous prolate epitrochoid with the number of teeth one less than the number of engaging members, the teeth on the other of said toothed members forming part of a continuous prolate hypotrochoid with the number of teeth one more than the number of engaging members.

2. In gear transmission a fast rotating member, a slowly rotating member, an intermediate disc mounted to turn eccentricall on said fast member, a set of engaging mem ers mounted evenly spaced on said intermediate disc. a member with tooth like projections engaging said engaging members on the outside, said member being held against rotary movement, the teeth on said member forming part of a continuous prolate hypotrochoid, with the number of teeth one more than the number of engaging members and another member also with tooth like projections engagin said engaging members on the inside, sai second member being fastened to said slowly rotating member, the teeth on said second member forming part of a continuous prolate epi-trochoid with the number of teeth one less than the number of the engaging members.

3. In a gear transmission a housing consisting of two parts joined in an axial direction, a fast rotating shaft, aslowly rotating shaft, an eccentric portion on said fast rotating shaft, an intermediate disc mounted rotatably on said fast rotating shaft, means for transmitting the movement from said intermediate disc to said slowly rotating shaft said said transmitting means consisting m art transmitting'means consisting in art of a series of evenly spaced pins and r0 ers, antifriction rollers to sup 'ort said slowly rotating shaft radially an axially in one of the parts of said housing, other antifriction rollers for supportin said fast rotating shaft radially and axial y in the other part'of said housing, a different set of antifriction rollers for supporting said fast shaft only radially in sai slowly rotating-shaft, another series of antifriction rollers for supporting said intermediate disc both axially and radially on said fast shaft and further antifriction rollers for supporting said rollers axially on said gins.

4. n a gear transmission a housing consisting of two parts joined in an axial direction, a fast rotating shaft, a slowly rotating shaft, an eccentric portion on said fast rotating shaft, an intermediate disc mounted rotatably on said fast rotating shaft, means for transmitting the movement from said intermediate disc to said slowly rotati shaft of a series of evenly spaced pins and rol ers, antifriction rollers to support said slowly rotating shaft radially and axially in one of the parts of said housing, other antifriction rollers for supporting said fast rotating shaft radially and axially in the other part of said housing, a different set of antifriction rollers for supportin said fast shaft only radially in said slow y rotating shaft, another series of antifriction rollers for supporting said intermediate disc both axially andraditoothed m said toothed-members forming substantially an eamdistant of a continuous prolate e itrochoi and the teeth on the other 0 said I bers forming substantially an equidistant of a continuous prolate hypotrochoid. y

7. In a gear transmission, the combination with a fast rotating member having an eccentric i'tion thereon, of a slowly rotating mem r, a transmission member mounted on said eccentric portion of said fast rotating member and rotatable bodily in response to rotation of said fast rotating member, means for causing an angular rotation of said transmission meinber in response to the bodily rotation thereof, means for rotating said slowly rotating member in accordance with movements of said transmission member, a bearing for said fast rotating member, a counterweight mounted on said fast rotating member for balancing parts moving eccentrically, said counterweight tending to splash lubricant into said bearin and shield means between said counterweig t and said bearing for reducing the splashing of lubricant into said bearing. I

In testimony whereof I hereunto aflix my signature. LORENZKQNRAD BRAREN ally on said fast shaft and further antifric- L tion rollers for sup rtin said rollers axially on said pins, all said anti riction rollers running in grooves provided directly in said different s afts and pins.

5. In a gear transmission, a' fast rotating member havin an eccentric'portion thereon, a slowly rotating member, a disc rotatably mounted on said eccentric portion of said fast rotating member, engaging rollers mounted on said disc, and two members zlvlith toothd like rejections in .en a ment wi sai engagihg rollers, one ofiai d toothed members be' fastened to said slowly rotating member an the other of said toothed members being held against rotary movement, the teeth on both of said toothed members forming substantiall a3 equidistant of a continuous prolate troc oi 6. In a gear tron, a fast rotatingmember havin an eccentric portion thereon, a slowly rotating member, a disc rotatably mounted on said eccentric portion of said fast rotating member engagmg' rollers mounted on said disc, and two members with tgoth like rojections in enga ment with sai engagihg rollers, one of sai d toothed members fastened to said slowly rotating member an the other of said toothed members being held against rotary movement, the teeth on one of 

